The present invention relates to a crushing apparatus for crushing synthetic resin molded products, which became useless, into the form of pellets.
Where molded products formed of polyvinyl chloride resin, acrylic resin or polyethylene resin became useless, wastes therefrom have to be treated, which poses a great problem. Under these circumstances, it has been proposed to reuse these wastes as a part of raw material for new resin products. That is, resin molded products which became useless are crushed into pellets, and the thus crushed resins are mixed into virgin pellets to produce new resin products.
For such a crushing apparatus, there has been proposed, for example, an apparatus generally indicated at 11 in FIGS. 1 and 2. The crushing apparatus 11 comprises a crushing chamber 14 having a molded product hopper 12 at a top thereof and a crushed pellet dropping opening 13, and a driving chamber 16 for accommodating therein a motor 15. Within the crushing chamber 14, there are provided two driving shafts 17 and 18 spaced up and down, said upper driving shaft 17 having a plurality of rotating blades 19 used for rough crushing mounted thereon and said lower driving shaft 18 having a plurality of rotating blades 20 used for fine crushing mounted thereon. The driving shaft 17 is connected to a shaft 22 of the motor 15 through a coupler 21 and the driving shaft 18 is connected to the driving shaft 17 through gears 23, 24. Crushed pieces 25 of waste resin molded products roughly crushed by means of a press or the like are discharged through the hopper 12 and roughly crushed by the rotating blades 19 while being guided by a guide plate 26 and fixed comb blades 27 provided corresponding to the rotating blades 19, after which they drop onto the lower rotating blades 20. The roughly crushed pieces are finely crushed into pellets by means of the rotating blades 20 while being guided by a guide plate 28 and fixed comb blades 29 provided corresponding to the rotating blades 20, and the pellets 30 are fed outside the crushing apparatus 11 through the dropping opening 13. Since such a crushing apparatus is provided with the roughly crushing rotating blades and the finely crushing rotating blades spaced up and down, the construction of the whole crushing apparatus becomes large-sized. Furthermore, the conventional crushing apparatus need be provided with driving mechanisms for two rotating blades, and the driving mechanism is disadvantageously complicated.